oil consumption

[datsun_nugget]

yea theres only the usual diesel noises going on. a vital piece of info i have forgot to add that the ute runs very hot under load i.e long inclines, and that contributes to the oil usage. e.g one of the trips ive made where its 80km from point A 2 B. from A 2 B its got alot of long and steep hills on the whole journey, ute runs very hot and at the end of the trip the oil wont read on the dip stick. the journey back,from B back 2 A im going down hill alot therefore the ute doesnt run near as hot and the result is oil consumption is not as much as A 2 B maybe even half as much. lots of blue smoke tho

 

[Old.Tony]

I'm sure oversized rings can be fitted but we're back to talking levers ... the downward force of the combustion in a petrol engine is nowhere close to the downward force of a diesel. The greater the force, the more leverage it would have @ the piston rings.

There's another issue with oversized piston rings, even if the combustion force were not pushing down on the edges of the rings trying to lever them out: that's the greatly increased blow-by.

Because there's a gap between ring 1 and 2, increasing the gap between piston and cylinder wall (by honing and choosing oversized rings instead of larger pistons) means the volume in the gap between the upper ring, lower ring and the piston and cylinder wall is greater. Since there's a gap in the rings, combustive gases can go into what is effectively a much larger pipe.

I would imagine that oversized rings would solve the problem on a very temporary basis if at all.

If it were my engine, I'd be grabbing slightly larger pistons and giving the thing a hone/rebore.

 

[crossy]

we could talk about to pros an cons of every option till the cows come home, at the end of the day the problems been found and all sorts of ways to fix it

 

[mikeathome]

I have the same setup in my Navara. The standard turbo oil return line is about 15mm and quite big enough - however if the crankcase ventilation unit on top of the rocker cover gets blocked you can get a build up of crankcase pressure which will try to stop the turbo oil draining - forcing the oil out both ends of the turbo shaft and into both the inlet manifold and the dump pipe.

The excessive oil consumption you report is pretty extreme. If it wasn't so bad I would suggest taking off the pipe that goes across the engine from the turbo to the inlet manifold and running the engine for a few moments. If the turbo seals are gone you will get a lot of oil blown out of the turbo and onto the underside of your bonnet etc (so put a rag there to protect it). Then the compression test. Ebay has a reasonable diesel gauge for under $100 if you can't borrow one that will let you compare the pressures in the 4 cylinders.

 

[datsun_nugget]

thanks for the advice mikeathome. so do u have the terrano td27t engine in ur nav to?

 

[mikeathome]

Yes I do. For a couple of years. I have a Hitachi HT12-1 Turbo that came with the motor - am trying to get the parts needed to replace the turbo bearings and seals etc but this particular turbo seems to be uncommon and nobody in Adelaide has (or can get apparently) the parts.

 

[datsun_nugget]

ive got a larger garret turbo on mine. have u butted the terrano engine up to the original navara gearbox. if so what clutch are you running in it. and have you had any issues with it.

 

[datsun_nugget]

Yes I do. For a couple of years. I have a Hitachi HT12-1 Turbo that came with the motor - am trying to get the parts needed to replace the turbo bearings and seals etc but this particular turbo seems to be uncommon and nobody in Adelaide has (or can get apparently) the parts.

just looked at my oil return line and its about 10mm im going to replace it with 20mm and have it connected to the sump if it isnt already. i also took the pipe of to the inlet manifold and there was oil inside it.

on top of the rocket cover at the back it has a round piece with an oil line coming out of it and that runs to the air pipe from the air box back thru the turbo so by blocking of the oil line and putting a catch-can on it should help. im not that good at explaning things i might try to take a couple pics and upload as a diagram

 

[mikeathome]

It is important that you do not create a restriction in the air pipe that vents the crankcase to the air intake pipe just before the turbo. As I said above the "round piece" on top of the rocker cover needs not to be blocked in any way. Introducing a catch can and associated piping can increase back pressure so much that the crankcase will not ventilate properly - particularly if you are getting blowby - and you will blow out the turbo seals. Make sure that the catch can fittings and the pipes are at least as big in diameter as is the standard pipe.

Someone has already said above that the Terrano TD27 motor has the same block (and all other components except turbo and injector pump and timing cover plate) as is fitted to the Navara. I simply put the manual Navara flywheel and clutch on the back of the Terrano motor and bolted in the new motor. I also swapped over the timing covers to get the tacho to work.

 

[Krankin]

we could talk about to pros an cons of every option till the cows come home, at the end of the day the problems been found and all sorts of ways to fix it

Yes I agree,


There's the correct way,
and,
there's the backyard way.

 

[crossy]

Yes I agree,


There's the correct way,
and,
there's the backyard way.

the diesel engine was invented in a backyard.....